Process of manufacturing insulating board



{ 4 sheets-s119151 1 ATTORNEYS.

W. H. MASON PROCESS OF MANUFACTURING INSULATING BOARD Filed Jan. 23, 1929 July 7, 1931.

July 7, 1931. w. H. MASON PROCESS OF MANUFACTURING INSULATING BOARD Filed Jan. 23, 1929 4 Sheets-SheaL 2 IN V EN TOR. #f7/m77 MW @5077. BY ag, fm ATTORNEYS.

July '7, 1931." y w. H. MASON 1,812,970

PROCESS OF MANUFACTURING INSULATING BOARD FiledJan. 2:5, 1929 4 sheets-she# 5 V EN TOR.

I N V/z//z'am afan.

ATTORNEYS.

`Iuly 7, i931. w. H. MASON v 1,812,970

PROCESS 0F MANUFACTURING INSULATING BOARD Filed Jan. 2/3, 1929 4 Sheets-Sheet 4 VAUAVAVMVAVAVAVAVAVAVAVAVAVAVAVAVAVAVA YA a o: o zu "y l 52 J5 I J4 9 l Patented July 7, 1931 i UNITED s'r'AlESy Pifvrlsn'rv OFFICE WILLIAM II. MASON, on LAUREL, MISSISSIPPI, AsSIefNoIi fro MAsoN'ITE conPoRA'rIeN, or LAUREL, MISSISSIPPI, A CORPORATION o F DELAWARE i PnozzEss or MANUFACTURING INSULATINQ BOARD Application ined- Ianary 2a, 1929. 'serial No. 334,387.

My invention relates to insulating boardV formed of veget-able fibre and has for oneof its principal objects the production of va board the exterionof which has a very high 6 degree 'of porosity, .and the exterior surfaces of which are hard and, dense.- Such` boards areof great strength, and can be manufactured at low cost.

Various raw materials can be used, provided-thel same contain cellulose together with lignin in Suliicient quantity to bind or affin or equivalent hydrocarbon at a temperweld the cellulose fibres together in compact relation when subjected to moisture, heat and pressure. 'II-he preferred materialis wood chips obtained from saw mill waste.

The raw material is rst disintegrated into fibres by any process in which at least the principal part of the lignin is retained, as, for example, the process disclosed and claimed in U. S. Patent No. 1,578,609,v granted March 30, 1926, in accordancel with which the fibre is obtained by'subjecting the wood chips in a closed high .pressure chamber to penetration by an elastic fiuid such as steam at high pressure, andprogressively discharging the same through a constricted outlet from said chamber while substantially maintaining the pressure in the pressure chamber, whereby the sudden expansion of the fluid is utilized for disintegrating the material.

The ibre thus obtained is recovered in a water bath and may be runthrough beaters or refiners if desired. Such fibres are of graduated Iineness and well adapted to be felted together. Very .little refining is necessary, and if desired may be entirely dispensed with.

`Thel ibre pulp so obtained should preferably be sized with suitable material distributed substantially uniformly throughout to rens der the inal product highly resistant to water and moisture. A suita le process for carrying out this step is disclosed and broadly claimed in my copending application Serial No. 277,382, filed May 12, 1928, and consists briefiy in subjecting the iibre to agitation in the water bath with melted petroleum, parature Suiciently high to prevent congealing of the hydrocarbon. y

In U. S. Patent No. 1,663,506 granted March 20, 1928, I have disclosed an insulating board having some of the characteristics of the present invention, togetherwith a process of producing the same.

-'.l ."he improved product and process herein claimed embody improvements whereby the cost of production is lowered and the product Will be uniform in quality and of predetermined gauge thickness. Such product is also characterized by extreme porosity of interior and extreme rigidity, compactness and stren th of exterior, or surface layers.

Re erence is hereby made to the accom# panying drawings of which i Figure 1 is a front elevation showing an lapparatus-suitable for carrying out the proci ess of my invention.

Fig. 2`is a side elevation of the sheet formlng box, partly broken away. n, Fig. 3 is a section on line 3-.-3 of Fig. 1. Fig. 4 is a front elevation, partly in section,

showing the sheet forming box and parts associated therewith, said box being in elevated position.

Fig. 5 is a side elevation of the press of movable platen being in its extreme upper position.

Fig. 10 is a similar view showin the platen depressed from' the position of Flg. 9 which means 1n operativeposition for gauging the posltion of the lower surface plate.

lnsulating sheet made in accordance with my mvention.

Fig. 12 is a similar View of a modification.

Fig. 13 is a Fig. 12.

In carrying out my invention the pulp mix# perspective view of the sheet of Fig. 11 is a detail section of one edge of an ture of lignin, cellulose and water is supplied f from a reservoir 1, provided with a mechanically dnven agitator 2, discharge chute 3 and gate 4, normally held in closed position by spring 5. A trough 6 is pivoted at 7 to the chute 3 and normally occupies the position shown in Fig. 1 for supplying pulp to the forming box 8. The box 8 is a rectangular structure, preferably of metal and open at both its upper and lower ends. It is mounted within guides 9 for vertical guided movement, and means, for example cables 10, running over pulleys 11 are provided for raising and lowering the same. When in its lowest position, the lower end of the forming box encloses the invertible drain box 12 and rests upon the bearings 13 by which the latter is supported, as shown in Fig-3.

The drain box 12 is preferably rectangular in form and provided with trunnions 14 which are rotatably mounted in the fixed bearings 13. lA screen 15 preferably of wire mesh extends across the topl of the drain box,

and a drain pipe'16 leads from the bottom thereof to a suitable waste pipe or recovery tank. -A sleeve or coupling 17 is provided which enables the pipe 16 to be readily dis- .s connected from the drain box wherever itis desired to invert the drain box. and in such case the pipe 16 will be rotated within the vertical bearing 18 to move it outside the path of movement of the drain box.

In practicing the improved process the forming box 8 being empty and in the position shown in Fig. 1, the gate 4 will be'opened and the pulp and water mixture allowed to flowinto said box, substantially filling it,

whereupon the gate will be closed. The water in said mixture immediately begins to drain away through the screen 15. into the drain box 12 and thence through pipe 16 to a suitor alone.

ablewaste pipe or recovery tank. The flow of water may be expedited .in various ways, as by applying suction to the pipe 16, either by vacuum pump or by extending pipe 16 downwardly to a sufiicient distancel to enable the descending wat-er column to apply suction to the'drain box. Another means for expediting the drainage of the water is shown as a weight l9 ,"Fig. 2, which rests upon the pulp mixture and may be used either in conjunction with the suction means above described A The weight 19 may hev raised and lowered by means of a cable 20.

ln place of the weight v19, I may use a. surface plate 21. Figs. 3 and 4, which is preferablv of metal, for example, chromium plated steel, and of slightly less area Ithan the in-l ternal area of the forming box so that it rests upon the pulp mixture and descends by gravity as the pulp mixture settles in the box. Obviously the plate 21 may be used either alone or in conjunction with the weight 19 and/or suction means previously described.

After the free water has been drained away, which is quickly accomplished,`the forming box 8 is raised by cables 10 to the position of Fig. 4, leaving the wet felted fibre sheet a upon the drain box with the surface plate 21 upon the upper surface of said sheet. Suitable securing means, for example a rope or cable 22 is passed around the drain box 12, sheet a and surface plate'21, the pipe 16 is disconnected from the drain box and swung to one side thereof, and the box is then turned upon its trunnions into an inverted position and the plate 21 carrying the pulp sheet a is deposited upon a roller conveyor 23. The fastening .means 22 is then removed, the drain box is rotated to its initial position, andthe pipe 16 is reconnected thereto. Upon lowering the forming box 8 to its initial position, the apparatus is in condition for the forming of another pulp sheet a.

Meanwhile the' surface plate 21 and t-he sheet a already formed will be carried by the conveyor 23 into the press 24. This press is of hydraulic type and comprises the usual frame and fixed top platen 25. There is also a movable platen 26 carried by the ram 27 which is mounted in cylinder 29. Steam pipes 28 are provided for heating the platens by applying steam at any desired pressure to the interior thereof.

The surface plate 21 rests upon a layer of wire mesh screen 30 which may be ordinary window screenv and is secured to the platen 26. lIt retards the flow of heat from the platen 26 to the surface 21 and pulp sheet a.

There is a rectangular metal frame 31 above the platen 26. In its normal position as shown in Figs. 5 and 7 its lower edge is above the upper surface of the pulp sheet a. The frame 31 is supported in such position by two pairs of cams 32 carried respectively by horizontal shafts 33 and 34. When in this position the upper surface plate 35 which rests upon said frame 31 and is removable therefrom is held firmly against the layer of wire mesh screen 36 which is similar t'o the screen 30 and is aflixed to the platen 25 for a similar purpose. The surface plate 35 is preferably of chromium plated steel.

The shafts 33 and 34 are geared together by bevel gears 37 and horizontal shaft 38, and there is a worm gear39 on shaft 34 in engagement with worm 40 mounted on a horizontal shaft 41. A clutch 42 operable by lever 43 serves to connect shaft 41 with a driving shaft when desired to'operate the cam shafts 33 and 34 for raising and lowering the frame 3l.

The lower edge 43 of frame 31 is beveled to facilitate entrance of sheet a withinsaid frame. Means are provided to act as gauges for determining the thickness of the finished sheet. As shown such means comprise headed pins 44 which are normally held in position of Fig. 9 by coil springs 45. They may applied thereto and the ram rises carrying with 1t the platen 26, surface plate 21 and lpulp sheet a. The sheet enters the frame 31 facelate 21 andl ,frame 31.

11e-I do not'limit myself to any particular values of moisture content, ineness of ing an Youtlet between the edges of thesurfibre,- pressure, heat of pl'atens, duration of application of heat and pressure, ultimate thickness of finished sheet, or relative densities 'of center and outside portions thereof, I

find that'a very fluid mixture of pulp fibre and waterl of an original depth of 6 orl 8 in the forming box, can be drained therein to a thickness or depth of approximately 18 to 24 and thereupon compressed inthe press toa thickness of 3/1, which may be accompl1shed by a pressure of 400 lbs. per sq. inch.

The heat of the platens may vary considering been shifted inward to limit the descent -of'the surface plate 21. The ram and platen ably, for example from 220' F.1to` several hundred degrees F. Y

The length of time during which the material is subjected to heat and high pressure is variable vand depends upon how thickit is .desired tomake the dense skin or surface portions, also upon the pressure, temperature and material employed. Ordinarily 10- to 60 seconds will suiice, and the ram and platen 26 are then dropped from the position of Fig. 9 to that of Fig. 10,'the pins 44 havmay be dropped quickly because although the sheet a is permeated by steam at high pressure due to the evaporation of a portion of its water content, there is no danger of damag- :ing the sheet by the sudden escape of steam therefrom since it firmly supported on both faces by the surface plates and at its edges by the frame 31. Sufficient clearance is Lprovided between` the edges of the surface plate 21 andthe frame 31 to permitthe ready escape of water and steam. The sudden reduction of pressure due to the dropping of the platen 26 from the positionof Fig. 9

' to that of' Figjl() causes the expansion of steam within the sheet a which together with the elasticity of the material in its interior which has not become se't immediately causes the sheet to expand `to completely fill the space between the -surface plates 21 and 35, whereby the interior of vthev sheet becomes very porous.

` The platen is held in the position of Fig.

10 for a sufficient time for the material to become sfet throughout the sheet, so that no further expansion will take place upon further dropping of the platen 26. This step in the process may occupy 2O to 60 seconds or more, in the instancel specified, in which,

l f the'platen 26 drops 1% from the position of Fig. 9to that of Fig. 10. Thisresults ina the purpose'of freemg the sheet a from the frame 31. This is accomplished by dropping the frame 31 from the position of Fig. 1() to that of Fig. 8 by-operating clutch handle 43 and thereby causing rotation of shafts 33 and 34 and cams 32.

The extent of downward movement of the frame 31 exceeds that of platen 26 and therefore the latter acts as an ejector for pushing the sheet a upwardly and out of the frame 31 so that it may bel readily removed from the press. The ram and platen wi-ll then be dropped to initial position, vthe frame elevated by means of shafts 33 and 34 and cams 32 to its 'original position, and the pins 44 released so as to be moved bythe springs 45 to their outer positions, whereupon the press may be used for operating upon another sheet a@ The sheets a after removal from the press may still contain a small amount v I of moisture which 'can be readily driven off gral therewith (see Figs. 11 and 12). Such i surface portions may ,be and A.preferably arc highly water resistant by reason of the use of sizing as set forth in my patent application Serial No. 277,382, previously mentioned'. The edges of the sheets, however, permit' the absorption of water into the porous interior of the sheet'and' in order to prevent such entrance of water, .I may apply thereto by any suitable means, for example, Water proof glue, a strip of paper c of sufficient length to completely enclose the four edges of the sheet. Such paper may be of water-resistant character.

The width of the paper strip or tape c may be the same as the thickness of the sheet as in Fig. 11, or,'if desired, 'a paper strip c of suicient width to enable its lateral edges to be folded over upon and glued to the side surfaces of the sheet may be used as shown in Figs. 12 and 13. lf desired, the pores of the edges of the'sheets may be closed by waterproof glue alone, thepaper strips c or c being dispensed with.

I claim:

1. A process of the character described,

comprising fiowing a fibre and water mixture into a vertically disposed form, draining 'water from the bottom of the mixture to form sheet, inserting same into a press, and expressing water therefrom.

2. A process of the character described, comprising flowing a fibre and Water mixture into a vertically disposed form, draining Water from the bottom of the mixture to form l I a sheet causing relative movement of form and sheet to separate the same, securing a surface plate on the upper surface of said sheet, invertingsaid sheet and surface plate, inserting same into a press, and expressing 'water from said sheet.

3. A process of the character described, comprising flowing a bre and Water mixture into a vertically disposed form, applying suction to the bottom of the mixture, draining Water from the bottom of the mixture to form a sheet causing relative movement of form and sheet to separate the same,

securing a surface plate on the upper surface of said sheet, inverting said sheet and Surface plate, inserting same'into a press, and

expressing Water from said sheet.

4. A'process of the character described,

,forming from a Water bath a sheet of ligninand-cellulose-containing fibre, subjecting thc same to pressure and'heat forsa time suflicient to form a compact layer on the exterior i surface, and thereupon quickly releasing the pressure on said sheet before the interior has become set While confining the edges thereof whereby the unset material is caused to expand. p

f 6. In a process of the character described, forming from a water bath a sheet of ligninand-cellulose containing fibre, subjecting same to pressurev and heat, relieving the pressure While confining the side edges of the is set, and thereupon removing the sheet from the press and drying it.

v In testimony whereof, I have signed my name hereto.

WILLIAM I-I. MASON.

sheet and causing same to expand to a predetermined thickness, continuing the application of heat until the material of the sheet is set, and thereupon removing it from the press.

7. In a process of the character described,

forming'from a Water bath a sheet of ligninand-cellulose-containing bre, subjecting same to pressure and heat, relieving the pressure While confining the side edges of the sheet and causing same to expand to a predeterminedthickness, continuing the application of heat until the material of the sheet yCERTIFICATI; or coRRECTIoN.

Patent No. 1,812,970. Granted July 7, 1931, wI

WILLIAM H. MASON. l

Itis hereby eertified that error appears in the printed specification of the above numbered patent requiring correction as follows: Pagel, line 46, for the word "petroleum" read petrolatum; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. t

y Signed and sealed this 1st day of September, A. D. 1931.

M. vJ. Moore,

(Seal)l l vActing Commissioner of Patents. 

